Relaying and Cooperation – A System Perspective

The paper considers various relaying strategies for wireless networks. We comparatively discuss and analyse direct transmission, conventional “multihop” relaying, and the novel concepts of cooperative relaying from the viewpoint of system level performance. While conventional relaying exploits pathloss savings, cooperative relaying additionally takes two inherent advantages of relay-based systems into account: the ability to exploit the broadcast nature of the wireless medium, and the diversity offered by the relay channel. Following a description of these concepts, we analyse the performance of such systems in an exemplary manner for power-controlled cellular and ad hoc CDMA systems. The resulting power savings and capacity improvements suggest that cooperative relaying may constitute an interesting candidate for future cellular and ad hoc network architectures.